Gas-operated machine-gun.



S. N; MQCLEAN. GAS OPERATED MACHINE GUN. APPLICATION FILED FEB. 11,1004.

Patented Got. 10, 1911.

4 SHLETS SHEET 1.

S. N. MGGLEAN. GAS OPERATED MACHINE GUN. APPLICATION FILED FEB.11, 1904.

Patented Oct. 10, 1911.

4 $HEETS-SHEET 2.

llWE/V rolf:

Mr/vEssEs:

WITNESSES:

S. N. MUCLEAN. GA OPERATED MACHINE GUN. APPLICATION FILED FEB. 11. 1994,

Patented Oct. 1%., 1911.

4 SHEETS-SEEET 3.

//v VEN 7013:

41, aim;

Patented Oct. 10, 1911. 4 SHEBTS-SHEET 4.

s. N. MQGLBMI. GAS OPERATED MACHINE GUN. APPLICATION FILED FEB. 11,1904.

ESSES; 7H5 W4; WM

UNITED STATES" PATENT OFFICE.

SAMUEL McCLEAN, OF. CLEVELAND, OHIO, ASSIGNOR. BY MESNE ASSIGNMENTS, TO

' THE AUTOMATIC ARMS COMPANY.-

GAS-OPERATED MACHINE-GUN. f

To alt whom it may concern."

Be itknown that I, SAMUELN. llICGLEAN, a resident of Cleveland, Ohio,have invented a new and useful Improvement is Gas-Operated Machine-Guns,which invention is fully set forth in the following specification.

My invention relates to improvementsfin breech-loading dischargeactuated guns, and

more particularly to gas-operated machine guns.

The objectof the invention 15 to improve and simplify the construction,operation and manufacture of these guns, to produce-again-having asmall-number of operating parts, which can be easily cared for, as-

sembled and disassembled without tools, inv

which the parts canbe interchangeable and readily. removed and inserted;and to attain certain advantages in connection with thebreech-mechanism, and in the feeding, firing and ejecting actions ofthe-gun, as more fully pointed out hereinafter.

The invention set forth in the accompanying drawings comprisesa'gas-operated ma.- chinr-gun having a reciprocating and r tatingln-ecch-block engaged by a gasdriVen piston to operate the breechmechanism, and

provided with an air-cushion to check the terminal movement of thepiston and to control the speed of tiring. The piston-rod also cnga andoperates an oscillating cartridge feed to consecutively feed thecartridges,

and cooperates with a scar and trigger to control the firing action ofthe gun. The frame of the gun is provided with a vertical magazine forretaining and consecutively feeding the cartridges, and this feed isprovided with spring-pressed feed-fingers en-' gaging with thecartridges to retain and control the consecutive feeding action of thecartridges.

Figure l is a side elevation of the gun, showing the rear part of theframe and cap in central section, and the forward part of the frame andassociated parts also in central section; Figs. 1 1 are details of themagazine and .clipf'Fig. 2 is a side eleva- .tion of the breech-blockand piston-rod showing the forward end of the breech-block in centralsection and the shell extractors in elevation; Fig. 3 is a plan view ofthe breech-block, looking up at its underside,

showing the drive-rod in cross-section, and showing a broken'centralsectlon at therein Specification of Letters Patent. P t t Q 10, 1911Application filed February 1 1, 1904. Serial No. 193,063.

end of the breech-block; Fig. 4 is a central sectional view of the rearend of the breechblock'and associated parts; Fig. 5 is a crosssectionalview of the handle part of the frame showing the firing dial andassociated parts; Fig. (Sis a rearend elevation of the gun; and Fig. 6details of the cartridge feed-finger'moi'inting; Fig. 7 is a rearele\;ation of the cartridg'e feeding fingers; Fig. 8 is a cross-sectionof the"cartridgefeeding device; Fig. 9 is a side elevation; and Fig. 10a front end elevation of the breech-block' and associated p'arts; 'Fig.11 is a central longitudinalsection of the breechblock and associatedparts, on the line 11-11,

Fig. 10, and showing the shell extractors in elevation; Fig. 12 is'a'diagramrnatic' view of the cam inthebreechtbck, show-ing'in sectionthe arm on thepiston'cooper'ating with said cam; Fig. 13' is" a 'brokensectional de- .breech-block, showing the cartrid e-ejector in elevation;Fig. 15 is a longitu inal sectional view of the cartridge feedingdevices, with parts thereof and the piston-rod in elevation; Fig. 16 isaside elevation of the plate carrying the cartridge-feed devices, whichlatter are shown in dotten lines; Fig. 17 is a central sectional view ofthe cylinder head and gas-controlling devices; and Fig. 18 is an endelevation of the same. Fig. 19 is a broken side elevation showing themanner of removably connecting the gas tube or chamber to the barrel;and Fig. 20 is a. front elevation of Fig. 19.

In the drawings, 1 is the gun-frame and 2 is the barrel secured withinthe forward end of the gun frame by screw-threads 3 en a in corresondinthreads in the b D b frame- The breech-end of the barrel is ciftout or chambered, as at 4, and the interior of this chamber is 'providedwith interrupted screw-threads 5 forthe engagement of correspondingscrew-threads on the breech-block, as will be hereinafter described. Thegun-frame is provided with a longitudinal cylindrical channel (5,extending from end to end thereof in line with the barrel, and a secondlongitudinal cylindrical channel 7 underneath and parallel with thechannel 6. The forward end of the channel 7 is in alinement with and isconnected to the tube 8 within which is-located the spring 9 whichserves to drive the gas-piston forside of the frame and has its forwardnose thrown inward by a spring 12, as shown in Fig. 1, so as to preventthe sleeve from moving rearward under the influence of the spring 9,unless the latch 11 is withdrawn. The rear end of the frame is closed bya cap 13, preferably secured to the end of the frame by interruptedscrew-threads 14, the form of the cap being such that when it isimposition it closes the ends of both of the cylindrical channels 6 and7. The cap 13 has formed therein a dash-pot 15 in alinement with thereciprocatory movement of the breech block, and this dash-pot serves asa buffer and a means 'of controlling the reciprocations of thebreechblock, as will be hereinafter more fully described. This cap hasalso formed thereon flanges 16 which may be engaged by any suitabletool, as, for

example, the shoulder bar, to operate the cap to unscrew it to releaseitfrom the frame. Between the cylindrical channels 6 and 7 is a slot 8extending from the rear of the frame. to a point considerably in advanceof the rear end of the barrel, this slot being for the purpose ofpermitting the arm on the iston rod, hereinafter referred to, to pro3ectup into the cylindrical channel 6 and engage the breech block foroperating the same. The under side of the frame is suitably slotted forthe purpose of permitting the play of the sear and trigger mechanism,and the frame is provided with a handle part 17 which is suitablyslotted and reamed out to form a housing for the trigger and the diskwhich controls the loading and firing action of the Weapon. 7

The breech block 18, best shown in Figs. 2, 3 and 4, 9, 10 and 11, isprovided with interrupted screw-threads of the usual or any suitableconstruct-ion, extending from the front thereof preferably to near therear end of the block, where there is a portion 19 that is free fromscrew-threads for the purpose of affording a bearing and guiding surfacefor the block within its cylindrical guide-way 6. This block ischambered out and has on its under side a slot 20, the forward portion21 of which is parallel with the axis of the block and the rear portionof which is oblique thereto, whereby a cam surface prsurfaces areprovided to be en- 'gaged by the arm on the piston rod of the gun foroperating the block. The particn r construction of this lot is bestshown in lfiigs. 3 and 12. On one side of the slot is provided anunbroken cam, surface 22 which is engaged by a corresponding cam surfaceon the arm 23 of the piston rod in the act of opening the breech. Theopposite part of the cam p rtion is provided with a cam surface 24substantially parallel with the cam surface 22 and a cam surface 25,formed at an angle to the cam 24. On the arm 23 of the piston rod thereare formed cam.

surfaces 26 and 27 for engagement with the cam surfaces 24 and 25, aswill be hereinafter more fully described. The forward end of the breechblock is bored out, as at- 28, for the passage of the firing pin and ismortised, as at 29, to afford seats for the extractors 30. Theseextractors are-similar in construction and are provided with the usualhook or claw for engaging the flange of the cartridge, and at the rearend'with an arm entering somewhat freely into the' mortise 29. Locatedin a suitable seat formed in the body of the breech block, is a.spring-pressed pin 31 whose spring acts to force the pin against theextractor and keep the same normally rocked forward in position toengage the flange of the eartridge, the extractor rocking about a pin32. This pin 32 is seated in a hole formed partly in the extractor andpartly in the body of the breech block. The extractor moreover isrovided with a suitable flange or tlnunbhold 33, and by rasping theextractor by said thumb-hold zsee Fig. 13) and forcing the same backagainst the spring-pressed pin 31, the extractor can be freed from theretaining pivot pin 32 and readily removed, the pin 31 being retained inits position by reason of the fact that the forward coil of its springis small enough to grip and frictionally retain its grip upon the pin,while the rearward coil of the spring is slightly larger than its seatin the block so as to secure frictional contact of the spring with theseat.

'Iherearward rhainbered-out portion of the breech block has alongitudinal slot 34 cut through its wall, and within this slot ismounted the ejector the form of a bar having an angular lug 3G turned toengage a shoulder 37 formed in the slot 34, the ejector being normallyheld in position with the lug 36 engaging the shoulder 37 by meansof'the spring 38 bearing upon the rear end of the ejector. The ejectoris also provided with a cam shoulder 39 and on its inner edge there aretwo lugs 40 which engage the inner surface of the walls of the breechblock, as shown in Fig. 14. In assembling the ejector the lugs 40 areplaced in position to register with grooves 41, formed in the side ofthe slot 34, and after the lugs 40 have passed through the grooves 41the ejector is advanced to the position shown in Figs. 9 and 14, andretained in its forward position bythe action engagement with theshoulder 37.

This ejector is in block, and the ejection of the Fig. 11 two springs 43and 44 are shown, 4-4

being the lighter spring and receiving and resisting the backwardmovement. of the piston plate 42 before it comes in contact with the 3ring 43. For the purpose of affording an a utment for the springs, andalso for the purpose of securing a piston packing to the rear end of thebreech block, there is formed on the interior of the breech block'anannular screw-threaded h'oulder, which is here shown in the form 0 aring 45 againstwhich the s ring 43 reacts. The shoulder formed by hisring 45 might be otherwise formed, but the construction wherein the ring45 is employed greatly facilitates the rapid .and cheap machining of theparts. The interior. of the ring 45 is screwthreaded, as abovementioned, and the plug 46 is screw-threaded therein so as to confinebetween its mushroom-shaped head and the rear end of-- the breech blocka packing 47 of fiber, or other suitable material, the diameter of whichis such as to cause itto fit snugly in the buffer cylinder 15 formed inthe cap 13 at the rear ot the gun-frame. The plate42 is provided with acentral opening or perforation 42" -and the screw-plug 46 has a likecentral opening or perforation 46, so that a restricted air passage isformed through the rearward part of the breech block for the purposehereinafter to be described. The piston plate is prevented from movingtoo far forward under the action of the springs by an annular shoulder4b, Fig. 1.1, formed on the interior of the block. block has also formedthereon a radial lug or rib 49 (Fig. 9)which travels in a suitablegroove 49 formed on the interior wall of the cylindrical chamber 6 ofthe gun-frame, thereby preventing the brrech block from turning, exceptwhen itis in position within the breech of the barrel, thus timing andcontrolling the locking and unlocking action of the bolt.

The operation of the breech mechanism, including the opening and closingof the breech, the placing of the cartridges in the receiver or chamber6- infront of the breech empty shell, are all performed by power from.the gases of nearthe muzzle. oinnigid with the piston extends rearwardthroughwthe tube 8 and into the cylindrical ,chamber '7 where it hasrigidly secured thereto the arm 23 shown in Figs. 2, 12 and The a gas'driven piston 135,

which chamber is 15. This piston rod 51 is surrounded by the coiledspring 9, and passes through the sleeve 10 (Fig. 1), and is providedwith a bottom rib 5E2qvhich. snugly fits in a cut-out channel 53 (seeFigs. 5 and 6) in the bottom of the chamber 7, thereby serving to steadyand guide the reciprocating movements of the piston rod. This piston rod"or drive rod has also formed thereon sear notches 54 and 55 forcooperation with the sear to control the loading. and firing action ofthe weapon. The firing pin, if desired, might be a loose pin mounted inthe breech block,

pin 56 rigidly secured to the arm 23in position to enter the bored-outfiring pin openbut as here shown it is in the form of a ing 28 in thebreech block. Preferably the 1 pin 56 is removably attached to the arm23,. The piston rod is also provided atone side, aiid preferably itsright-hand side, with a cam, preferably in the form of a cam groove 57,extending forward and downward from its rear end for the purpose ofoperatively engaging the partsgto effect theplacing of, the cartridgeswithin the receiver as. will be hereinafter described.

The gas-driven piston 'is'located in a gas chamber 59 at the forward endof the gun, preferably supported upon the gun-barrel by means. of anysuitable bracket. Communication is established between the bore of thegun and the gas chamber 59.by an opening or openings leading from thegun bore to said chamber, in which chamber provision is .made'forcontrolling the gas pressure in the chamber. The means for effectingthis control are shown in Figs. 17 and 18. The forward end of the gaschamber 59 is closed by ascrew-plug 60 inserted therein, through whichplug openings or ports 61 are formed,'and all of these openings or portsare controlled by a valve 62 held yieldingly to its seat by a spring. 63reacting between the valve and the head of a mushroom-shaped screw-64,secured in the central portion of the screw-cap or plug (30, as will beclearly understoodfrom an inspection of Fig. 17. Preferably the hub orcentral portion of the cap 60 projects outward slightly, so as to forma. guide for the valve 62 and is, or may be, polygonal in form in orderto more effectively perform its guiding functions, as is shown in dottedlines in Fig. 18, where 65 indicates the polygonal guide for the valve62.

The tension of the-spring '63 holding the ValVQ'GQ to its ,seat isdetermined by the screw 64. \Vhen the gun is fired and the gases enter.-'chamber 59, if the pressure is above the desired amount, the gasesentering port 61 raise the valves 62 against the tension of its springand escape until the pressurev injthechamber 59 is reduced to the desird point, when the valve promptly closes. This construction,' not only eeetively controls the pressure of the gas in the chamber 59, but is onewhich is readily removed in order that the chamber may be inspected andcleaned.

The gun is provided with a substantially vertical magazine 66 placed toone side of the gun frame, preferably the right-hand side as shown inFig. 6, the magazine being prodded with grooves or guide-ways 67 asshown in dotted lines in Fig. 6, for engagement with the flanges of thecartridge or cartridge clips as the case may be. Adjacent to the bottomof the magazine there is an opening formed in the side of thecylindrical chamber or receiver (3, and a table 68, shown in dottedlines in Fig. 6, is formed in the bottom of t1": magazine 66 to receivethe lowermost cartridge. The outer wall of the magazine at its dowerpart is composed of the flanged plate 69 (see Figs. 6, 8, 15 and 16).This plate is held in position against the flanges in the wall of themagazine by springs 70 (Figs. 6 and 8) which react between the gun frameand socket bearings 71; (Fig. 15) in the plate to hold it'pressedoutward firmly against the retaining flanges 72, 73, of the magazine.

Referring now to Figs. 15 and 16, this plate 69 has formed on itsinterior three pairs of brackets 74, 75 and 76, which are her-ed out inalinement to form the bearings fdr the rock shaft 78, which shaft hasakeyway 79 (Fig. 8) extending along its length.

Feed levers 80, 80, are mounted on the rockshaft 79 between therespective pairs of bearing brackets 74 and 75, and anoperating arm rlever 81 (Fig. 8) is mounted on the rock-shaft 7S bet-ween thebrackets.76. The feed levers 80, 80, and the arm or lever 81 are allprovided with a key-way, as 82, (Fig. 8) and a key 83 enters the key-way79 on the shaft and the ways 82 in the arms and lever 81, therebyeffectively securing the said parts to the shaft and compelling them toturn therewith and yet permitting the ready disassemblage of all theparts by merely removing the key 83. The rock-shaft 78 is normally heldin the positions shown in Figs. 6 and 8, z'. e., with the feed levers 80in their outermost. position, by the action of a coiled spring 8% (Fig.15) one end of which is secured to a collar 85 attached to therock-shaft 78 by a set-screw 86, the other end of' the spring beingsecured to the bracket plate (39 at 87, so that the shaft is rocked inone direction against the tension of the spring 84, and is by the springreturned to its normal posit-ion when freed from the acti..n of thedrive rod, as will be hereinafter explained.

For the purpose of holding the bottom cartridge in the magazine in placeupon the table 68, until such time as itis to be fed into the receiver,and-furthermore, for the purpose of steadying the feeding action so thatthe cartridge will be accurately thrown to its position in the receivenby the feed levers 80, the cartridge feed fingers 88 are employed, whichbear yieldingly upon the cartridge while it rests upon the table (38 andmaintain their yielding bearing upon the cartridge during the action ofthe cartridge feed levers 80. These cartridge-feed fingers may be placedon either side of the magazine without materially departing from thespirit of the invention, and as here shown are located upon the,left-hand side'thereof. They have both an oscillating and areciprocating action 'which is secured by pivotingthe fingers 88 to ashank 89 (Fig. 7)., a spring 90 engaging the two parts so as to normallyhold the feed-finger 88 in the position shown in Fig. 7. This shank 89enters a channel 91, removably mounted in the side walls of the magazine(see Figs. 6, 6 and is downwardly pressed by a spring 92, the normalposition of the parts being as clearlyshown in Fig. 6. lVhen thecartridge-feed levers 8O advance from right to left to throw thecartridge into the gun, the cartridgefeed fingers 88' bear upon thesurface of the cartridge, as shown in Fig. 6, but swing upon their pivotpins and at the same time slightly rise so as to allow the cartridgetopass under the lower end of the feed finger. It will be readilyperceived that this operation holds the cartridge at all times, firmlybut yieldingly against the table and the cartridgefeed levers 80, andprevents any overthrow or nnsplacement of the cartrldge whlch mightcause jamming or other inaccuracies in the loading action.

groove 57 upon the rear end of the piston rod, the lever entering therear end of said groove when the breech block has been drawnsufliciently to the rear to permit the cartridge to enter between theforward end of the breech block and the rear end of the barrel, when thefurther rearward movement of the piston rod serves to depress the rearend of the lever 81, thereby rocking the shaftand throwing thefeed-levers 80 inward and carrying with them the cartridge, as will bereadily understood from an inspection of Figs. 6 and 8. As soon as theend of the lever 81 has reached the point 93 in the slot 57 (see Fig.2),- the spring 84: on the rock-shaft acts to return the shaft to itsnormal position, the end of the lever 81 traveling in the part 94: ofthe groove in the drive-rod, as shown in Fig. 2.

For the purpose of drawing the piston rod rearward either to open thebreach or disassemble the parts, a sliding bar 95 (Fig. 6) is mounted ina slide-way in the frame and has a handle 96 secured thereto, as welllic- registers with a slot 99 in the slide-way when the handle israised, at which time the lug 97 lies in front. of a correspondinglug100 secured to the piston rod 51, as is clearly 5 shown in Fig. 6. Bygrasping the handle 96, raising it until the shank registers with slot99 and drawing the same-rearward, the ])lSt()11-lOd may be withdrawn tothe rear for the purpose of opening the breech or, if the cap 13 hasbeen removed from the gunframe, it maybewithdrawn rearward so as tobring the breech-block out of the chainher 6, when it can be separatedfrom the piston rod. Before it is possible, however, 15 t0 thus withdrawthe piston rod so far to the rear, it is necessary to operate the catch11 so as to free the sleeve 10 which forms the abutment for the spring9. This being done all of the parts, piston-rod, sleeve, zosprin g andpiston,-as. well as the breechblock, can be entirely withdrawn. It willbe readily appreciated that the only tool necessary forthusdisassembling the parts will be such'a tool as would "fit in betweenthe flanges 16 upon the cap '13, to give it a partial turn in order todisengage'the inter-' rupted screw-threads thereon, and as has beenhereinbefore stated, the shank of the shoulder bar would form aneffective tool for this purpose. Moreover, for disassembling the partsconnected with the feeding of the cartridges into the receiver, it willonly be necessary to' push in the lower part of the bracket plate 69against the tension of the springs 70, therebytreeingthe flanges on theplate from the upper flanges 72 upon the magazine wall, when the entirebracket plate can be'withdrawn from the gun.- A

very efiicient means for thus pushing the 40 bracket plate in is securedby forming flanges 101 (Figs. 1. (i and 8) upon the bracket plate. whichflanges are adapted to receivethe shank of the shoulder bar which maythen be utilized for pushing the lower part of the bracket plateinward-as above sug gestcd. The bracket plate having been re-' movedfrom the magazine, it is only ncccs;

sary to push out the key 83, whcn all it-the parts, including the feedlever 80, operating lever 81, and the. rock shaft 78, can he re moved.

From the foregoing, it will he appreciated that tlic entiredisasseii'ihliug of the gun can be readily atwoniplished without the use55 of any special tools, and can be as .rcadily and quickly asscniliiledwithout tools.

Referring now to the sear a iid trigger deviccsfand the means forcontrolling the:

' and then lip ofi into engagement with the same, as shown-in Figs. 1and :'1,the scar I02 is pivotally mounted in a lower extension of thet'rauic. living pi'cfcrablv pivoted to a I hank pin 103 which hasbearing upon a spring 04. and the sear itself being nor mally held in anelevated position by a scarspring :05. The scar itself is provided withi pulled. v

a sear-shoulder 106. for engagement with the sear-notches 54 and 55 uponthe piston or drive-rod, 'and hasat its rear end a notch 10?. Thetrigger 108 is pivoted at 105), haviiig an oblong pivot bearing 110, asshown by dotted lines in Fig. 1', and is iioriually held with itssear-engaging nose in elevated position by the trigger-spring 111'. WhenFigs. 1 and Thisdial is secured to a pin 113., rigid with ahandle114,-and a spring 115 reacts between the dial and a' faceplate lltClQSingthe recess forming the housing for the dial. The handle 114 hasformed thereon a lug- 117 (Fig; 5)

for yie-ldinglv engaging recesses or notches 1 18, 119 andl20,.all='of,which are clearly shown in Fig. 1,'and.an'other similarnotch which does not appearin Fig.".-1,-sinc'e itis covered by thehandle 114. The dial'plate v is provided. with shoulders 121, 122,123and 124, which shouldersact to limit :the movement of. the trigger byreason ofv the engagement of a. lug 125mm the t-riggcrand which plays ina slot 126 (Fig.5) so, as to come in contact with thelfiring dial as'thetrigger By turning the dial to the position shown in Fig. 1, theSl1011ld01 12 3 on the dial is' brought into position. so as to allowthe trigger tolbe pulled far enough to 'entirely depress the sear belowboth of the scar notches on the, piston-rod 51, and theweapon-automatically loads and "fires as long as car tridgcsarc fedthereto from the inaga'lzinc, the operator ii ierely holding the triggerwith the lug 125 firmly against the shoulder 123. By adjustnient'tothesother positions iii'dicatcdby the notches 118. 11$) and 120, thetrigger may lmeithcr locked so that it can- 'Jltit be tircd at, :1lladjustcd so that the sear will engage at each discharge with the scarnotch 54 to hold the hi-i-cclropcn for single loading or with the scariiotch for I magazine loading but single firing, the form of the variousshoulders being such as to either permit the trigger when pulled torotain the sea r entirely out ot-thc line of both ni'itches. as when itiuigagcs the upper surface otthe 5011110! to permit it to first engagethe upper surface, withdraw the sear from engagement with the sear notch54:,

notch 107 which will permit the sear to rise into cngagciucnt with ,thenotch 55,-when a Furthi-r pull will discharge the gun. l ReferringtoFigs. 19 and 20, the gas tube 8, the rca r portion of which is shown inFig. 1 attached to the gun frame, is supported at its forward end uponthe muzzle of the bartube or chamber. This portion of the tubeconstitutes a cylinder 59 which, as before 10 stated, is in directcommunication with the bore of the barrel through suitable channels orpassages shown in dotted lines at 134. Preferably there is a pluralityof suchchannels as shown, though manifestly a single channel ofsuitableshape and size might be employed, if desired. In Figs. 19 and 20the end closure or cap of the gas tube, as shown in Fig. 17, is removed.This construction provides for the ready assemblage and dis- 20assemblage of the tube at the muzzle end of the barrel.

The operation of the gun will be readily understood. The gases enteringthe gas chamber 59 through the openings 134, drive the piston 135rearward and with it the drive rod or operating slide 51. In itsrearward movement the arm 23 on said slide first travels in the-portion20' of the actuating slot in the breech block and then impinges 80 uponthe cam" 22 which turns the breech block so as to unlock it, and on itsfurther rearward movement the arm 23 strikes the spring-pressed plate orcap 42 covering the perforations 42" therethrough. The spring 44 takesup the first part of the blow of the slide and is subsequentlyreinforced by the spring 43.- The breech block is then driven rearwardand just before it reaches its full open position, the piston on the endof the 40 breech block enters the dash-pot 15 in the cap of the chamber6 and thus serves to relieve the shock and slow down the action of thebreech block by reason of the air confined in the dash-pot, the air veryslowly escaping either past the piston or through the perforation 46,and the perforation 42 in the spring plate. As soon as the breech blockhas come to rest, the springs 43 and 44 act to slowly advance the arm 23of the slide until the cam face 26 on said slide is brought into contactwith the portion 25 of the double cam on the right-hand side of theslot, in which position, assuming the firing 3k 112 to be set forsingle'load and firing, tie notch 54 on thedrivc-rod is engaged by thescar and the parts are held in this position. A pull upon the triggerreleases the sear from the notch 54 and permits the advance of theslide, and with it the arm 6 23, under the influence of the spring 9.During the rearward travel of the bleach block, the lug 49 engages andtravels in the groove 49", Fig. 1, so as to prevent the rotation of thebreech block during its rearward travel, and

when the drive rod is released from the sear the engagement of the cam25 with the cam 26 forces the breech block forward until the lug 49 isreleased from the groove 49 which only occurs whenthe breech block hasentered the breech chamber of the barrel in position to be turned tocause its interrupted threads to turn and lock with the correspondingthreads in the breech of the barrel. The advance of the arm 23 at theinstant the sear engages the notch 54 relieves the pressure of said armon the spring plate 42, and uncovers the port 42 therein so that air isenabled to enter through said restricted port and the re stricted port46 into the dash-pot, the spring plate 42 being slightly advanced infront of the spring 43 by the lighter spring 44. \Vhen the slide isrelieved from the restraining action of the sear, the arm 23 advances,acting upon the cam 26 and the breech block is prevented from turning bythe engagement of the lug 49 on the breech block with a groove 4'9 inthe chamber .6. The block having been fully entered in the breech of thebarrel, the action of the cam 26 on the cam face 25, commences theturning action of the block to lock it and the cam 27 on the arm 23 thenengages the cam 24 and completes the locking action. Owing to thedifference in pitch between the earns 24 and 25 the tendency of thebreech-block to turn while the lug 49 is in groove 49 is loss while cams26 and 25 are engaged, than while cams 2-7 and 24 are acting. The suddenbringing forward of the breech block and the slide under the influenceof the spring 9, when theslide is released from the engagement of thesear, is slowed down and shock prevented by the engagement of the pistonon the rear of the block with the dash-pot, the restricted passages 42and 4G permitting air to enter, which prevents too great a suction, butbeing in small enough quantity to cause a slight retardation 'of theclosing action. In the act of opening the breech, the shoulder 39 uponthe ejector impinges upon the corresponding shoulder 39 (Fig. 6) in thereceiver and suddenly throwsthc ejector in ward, thereby forcing thecartridge out through the opening 39 in the receiver, indicated by thedotted lines at the upper lefthand part of Fig. (i, this opening 39being the usual and well-known form of cartridge ejector opening. In theopening movement of the rm-iprocating slide, 51, just after the breechblock has been opened the full length of a cartridge. the arm 81 (Fig.8) of the cartridge feeding device enters the cam gro'ove 5'7 at therear end of the slide. thereby depressing the arm and advancing the feedlevers 30 toward the receiver. carrying with it the cartridge restingupon the table 68, the movement of the cartridge, however, beingsteadied by the action of the cartridge food lovers 88, as previouslydescribed. "-he action of the cartridge is, furthermore,

steadied-and its seat upon the cartridge feed levers 80. is renderedmore firm and secure by reason of brackets 80 projecting laterally fromthe side .of the feed levers, as shown in full lines in Fig'lS and indotted lines'in Fig. (3, said brackets having an upper'surface curved toconform to the outline of the cartridge. The tension of the-gasesjin theI gas cylinder 59 and the violence with which ill); impel the pistonaudits attached slide rearward, is .dete'rmined by the'adjustment of thescrew 64: bearing upon the 5 ring 3,

- which controls the valve 62 over t e ports shaft engaging grooves intlrelevers, or the,

61 at the forward end of the gas chamber.

- It will be observed that the entire structure of the'gun .is verysimple in character, and one readily assembled and disassembled withoutthe-employment of tools. By de-' pressing the spring-catch 11 andremoving the cap 13, the piston and slide, the spring 9 and the breechblock can all be readily and,

entirely withdrawn from the gun. It has heretofore been explained how,by simply pressing in the bracket plate 69 carrying the cartridge feeddevices, it can be readily removed from the. gun, carrying with it allof I block, a piston thereon having an 0.1! port extendingthere'through, a chamber-within the elements which operate to' feed the"cartridges,'-imd by the removal of the key which connects the plate,the'rock-shaft and the levers thef eon," the same may be all'entirelyseparated." Itwill be understood that-this key might, if desired, beintegral with /the levers mounted on the shaft might have keys formedfor engagm'ent with a longitudinal groove in the shaft. Moreover, itwill be understood that tho tcnsion of the spring 84' on said shaft, canbe adjusted by merely loosening the set-screw 86 and turning the.

collar 85 around the shaft in either direction, suitable depressions, ifdesired, being formed in the'shat't to afford a secure hold on theset-screw. r

. Referring to the extractors,-it has already been explained how, byreason of their con struct-ion and method ofmounting, they can bereadily disassembled by simply pushing them slightlybackagainst the pins31, and thereby freeing them. from the pivot pins 32, after which theycan'be lifted out of theextractor seats. The ejector may also bewithdrawn from its seat by simply pressing it rearward against thetension of the spring 38 uut' the lugs 40 on the ejector register withthe grooves 41 in the side faces of the slot 34, when the ejector can beelevated out of the slot 34. The piston and butter spring mechanism atthe rear end of the' breech block can be entirely disassembled by unthcscrew-plug 46 and the ring 45, when :1 moved. Usually the cartridges tobeinsertcd in the ma azine'are contained in a cartridge clip 140 fig.1") of any desired or suitable construction and for the purpose ofretain actuated by the gases of disc of these parts can be readily reisinserted into the magazine, said clip'is provided with a spring-pressed'retainin catch 141. This retaining catch is rovide with a lug, orpreferably a pair of age 142,

while the. magazine. has a cam surface 143 near its lower rearend' soformed and p0sitioned as to enga e the cam'lugs 142 on the catch 141 andwit draw said ca'tchfrom-um derneath the cartridges as the clip isforced into the magazine. The bottom portion. of this cam surface is inthe form of a rounded undercut 11 144 which actsto. engage the lo 142 anthereby hold-the clip in the magazine, the spring of the catch .141yielding sufficiently to free the clipwhen force is applied to withdrawit from the magazine.

Vhat is claimed is: a

1. In a gun, the combinationof a breech block, a piston thereon havingan air port extending therethrough, a chamber within which the saidblock reci'procates, and a dash- 0t in said chamber in position to beentered y said piston on its terminal rearward movement. 2. In a: gumthecombination of a breech block and controlling the passage of air throughsaid port, and a dash-pot in said chamber in position to be entered bysaid piston on its terminal rearwardfmovement. 4. In a gun, thecombination of a breech block, a piston thereon having an air portextending therethrough, a chamber within which the breech blockreciprocates, a discharge-actuated slide imparting reciprocatingmovements to the block and controlling 'the passage of air th ough saidport, and a.

dash-pot in said chamber in position to be entered by sald piston on itsterminal rearward movement.

5. In a gun, the lcombination of a breech block, a piston thereon havingan air port extending therethrough, a chamber within which the breechblock reciprocates, a slide arge impartin reciprocating movements to theblock an controlling the passage ofair through said ort and a dashwt insaid chamber in osition to be entered by said piston on its terminalrearward movement.

6. In a gun, the combination of a recipro eating breech block, abreech-block-operating 13L slide, and a pair of buffer springsinte'rpose between the block and slide, first one and then both of saidsprings acting to cushion the blow of the slide upon the block.

7. In a gun, the combination of a reciprocating breech-block, adischarge-actuated breech-block-operating slide, and a pair of buffersprings interposed between the block andfslide, first one and then bothof-said springs acting to cushion the blow of the slide upon the block.

piston" on the rear end of-the block, and a breech-bloek-operating Islide engaging the said piston plate or cap and controlling the porttherein.

t 9. In a gun, the combination of a receiver chamber, a dash-pot inconnection therewith,

a breech-block forming a piston for engagement with saiddash-pot, anair-port leading irom said dash-pot, and a. breech-blockoperatingelementcontrolling said port.

10, In a gun,-the cornbination of a receiver chamber, --'a dash pottherein, breech-block forming a piston-for engagement with saiddash-pot, a spring-pressed plate in front of the piston and having-aport' for the passage of air into and out-of said dash-pot, and abreech-block -1 operating element controlling said ports,

'ILFIna gun, a receiver-chamber and a dash-pot in line therewith, abreech-block forming a piston movable in said chamber and dash-pot, a.spring-controlled plate car- .ried by said breech-block, a port oropening through saidpiston and plate and breechblock-operating meansopening and closing said port. V 12. In a gun, a'brehch bl'ock having anejector seat in the form ofa slot through the walls of the block, anejector seated said slot. andhaving'lugs engaging the intcrior-j surfaceof the block, and grooves forum-:1 in one \\1Llli0f the slot andarranged to "register withlsaid lugs when the e ector slightly shiftedfrom normal position,

in position fangLi-cmoved therefrom.

; l3. Ina gun, abrecch-bloclg having ail ejector scat inthe form of aslot through the wall of the block with grooves extending acmss one faceof the slot, a n ejector mountwhereby the ejector may be .readily'placcdydifl-iii" said slot and having lugs spaced to if "register with saldgrooves when the e ector is'slightly to th rear of its normal position,

a hearing point on the breech-block around which the ejector normallyturns. and a spring-holding the ejector against said point.

I4. In a gun, a breech-block having a cartrldge-ejector seat in the formof a slot through the walls of the block, said slot having a groove inone of its faces, and an exterior recess at oneside of the groove, and,

an ejector seated in said slot and having a lug fitting in said recessso as to have 1on gitudinal play therein and also having a side lugregistering with said groove when'g -i.

the ejector is in its rearward p .ition.

15. In a gun, a breech-block ht ving a carlugs registering with saidgrooves only'when the ejectbr is shifted from its-normal posi-- .75tridge-ejeetor seat in the "form of a "slot tion, a cam on.theiejectorj-and-a shoulder in the receiver for operating the ejector.

17 In a, air, a breech-block having an in-. terior chain 'er, alongitudinal slot through the walls of the block into said chamber andhaving a groove formed in one of its faces and a 'recess'on the, side ofsaid slot of greater widththjansiiid groove, an ejector havingtwo lugsone of which has longitudin l. movement in said recess and the other ofwhich normally engages the inner Wall of the block, but registers withsaid groove when the other lug is at the rear of its recess. v 1

d8. In a gun, a chambered breech-block having a slot in its wall, and anejector, seated in said slot and having. a lug at one end engaging theexterior of the block and having another lug engaging the inter or ofthe block.

19. In a gun, a chambcred'breech-block having a slot in its walhanejector seated in said slot and having a lug at its rear end engaging ashoulder on the outer part of the block and another lug engaging theinterior wall of the block, and a-spring holding the first-mentioned.lug yieldingly against said shoulder.

"20. In agim, a receiver, a reciprocating and rotating chamberedbreech-block having a longitudinal slot in its wall, an ejector seatedin'said slot and having a. lug at one end engaging the exterior of theblock and another lug engaging the interior of the block, a cam ontheejector and a. shoulder on the receiver in the path of. the cam on theejector, and a gas-driven piston operatively engaging the breech-block.

- Cit breeclrblock, a piston on the rear end of the block, a butter orcushion carried by the block,a receiver having a dash-pot in line withthe breechblock, and a gas -driven. slide operatively engaging saidblock and also engaging said buffer or cushion,

In a gun, a gas cylinder connnunicating with the gun bore, a piston insaid cylinder, a removable closure for the front end of said cylinder,ports through said closure and an automatic relief valve controllingsaid ports.

23. In a gun, a gas cylinder communicating with the gun bore, a pistonin said cylinder, a removable closure for the front end of saidcylinder, ports through said closure, a valve controlling said ports,-aspring hearing on said valve and a screw regulating the tension of saidsprin 24; In a gun, a barrel, a gas cylinder commun-icating with the gunbore, vent ports to the atmosphere, a piston in said cylinder, and avalve coiitrolling said ports independent of said piston. 7

'25..In a gun, a gas cylinder, a piston therein, a port connecting thebarrel with said gas cylinder on the working side of said piston, a ventport or ports for said gas cylinder leading fronr the working side ofthe piston to the atmosphere, and a springpressed valve controlling saidport or ports. 26. In a gun, a tgas cylinder communicating with thegunbore, vent ports to 'said' cylinder, a spring-pressed valvecontrolling said ports, and a. SCI'QWfldJIlStlD thetension of saidspring.

27. In a gun, the combination of a breech block, agasdriven slideoperatively engagin'g said block, chambers in which said block and slidereciprocate, a collar surrounding saiil slide within one of saidchambers, a catch restraining said collar against rearward movement, anda spring reacting between said collar and a. piston on the slide.

In a gun, a ln.-c.ccl1-block, a gas-driven piston operatively connectedthereto, a chamber within which said piston works, and automatic meanslimiting the gas pressure within said chamber.

'21). In a. gun, a piston actuated by the gases of discharge, andautomatic means limiting the gas pressure on the piston to apredetermined degree.

3-0. In a gun, a gas'chamber communicating with the bore, a vent port orvent .ports to the atmosphere, a. reciprocating piston in said chamber,and an automatic relief valve independent of said piston controllingsaid vent pirt or ports.

' 31. In a magazine gun, a cartridge-feed mechanism for inserting thecartridges into the receiver, a removable bracket plate upon which saidfeed mechanism is lllULllllt-i'i, and

discharge-actuated means operatively connected to said feed mechanism.32; In a magazine gun, a rock-shaft mounted in a removable bracketplate, cart-ridge-feed levers on said rock-shaft, a discharge actuatedslide and operative connections-between said slide and rock-shaft.

In a magazine gun, transversely-operating cartridge-feed mechanism and aremovable plate on the side of the magazine supporting said feedmechanism.

34. In a magazine gun, a bracket plate having flanged engagement withthe walls of the magazine, cartridge-feed mechanism supported on saidplate, and yieldiir devices holding said plate in engagement with theflanges on the magazine.

35. In a magazine gun, a removable bracketplate forming the lower wallof the magazine, and cartridge-feed mechanism removablysecuredto saidbracket plate.

36. In a magazine gun, a bracket,- plate yieldingly held in flangedengagement, with the magazine, bearing'brackets on said plate, anoperating lever and a. cartridge-feed lever held between said bracketbearings, and a rock-shaft passing through said levers and brackets andkeyed to" saidlevers.

37. In a magazinegun, a removable bracket plate, bracket bearings on theinte -ri'or of said plate, a cartridge-feed lever and an operating leverlocated between said bracket bearings," a rock-shaft passing throughsaid bearings and said levers and a key securing said levers androck-shaft together.

38. In a magazine gun, a removable bracket plate, a plurality of hearingI) 'ackcts on the face of said plate, a cartridge-teed lever andoperating lever located between said bracket bearings, a. rock-shaftkeyed to said levers and passing through said bearings, and a gasoperated slide engaging sail ope 'ating lever.

39. In a magazine gun, an oscillating and reciprocating cartridgeteedfinger and means holding the same in yielding contact,

with the cartridge.

40. In a magazine gun, a cartridge-teed finger, a shank to which saidlinger pivotally .united, a guideway within which said shank is located,and a spring pressingupon said shank, whereby the cartridgefeed tin gcris enabled to both oscillate and reciprocate under the feeding action ofthe cartridge. I

41. In a nmgazine gun, a spring-pressed rcci 'ii'ocating and oscillatingcartridge-feed finger removably mounted'in the magazine.

42. In a gas-actuated automatic gun, the combination of a breech block,a gas-driven piston opcrativcly engaging the same, a spring for movingthe piston forward and an adjustable abutment for the rear end of saidspring whereby it may be put under tension or the tension thereof bereleased at wi 1. c

- &3. In a gas-actuated automatic gun, the combination of areciprocating piston rod and a breech block operatively connectedthereto, with a spring for impelling the piston rod forward, a sleevesurrounding the piston rod and forming an abutment for the c 10 rear ofsaid spring, and means for adjusting said sleeve upon the rod to placethe springspecification in the presence of two subscrib- 15 ingwitnesses.

' SAMUEL N. MOCLEAN. \Vitnesses:

S. T. CAMERON,

TM. B. HERKANE.

